Identification of Dental Implant Systems Using a Large-Scale Multicenter Data Set.

This study aimed to evaluate the efficacy of deep learning (DL) for the identification and classification of various types of dental implant systems (DISs) using a large-scale multicenter data set. We also compared the classification accuracy of DL and dental professionals. The data set, which was collected from 5 college dental hospitals and 10 private dental clinics, contained 37,442 (24.8%) periapical and 113,291 (75.2%) panoramic radiographic images and consisted of a total of 10 manufacturers and 25 different types of DISs. The classification accuracy of DL was evaluated using a pretrained and modified ResNet-50 architecture, and comparison of accuracy performance and reading time between DL and dental professionals was conducted using a self-reported questionnaire. When comparing the accuracy performance for classification of DISs, DL (accuracy: 82.0%; 95% confidence interval [CI], 75.9%-87.0%) outperformed most of the participants (mean accuracy: 23.5% ± 18.5%; 95% CI, 18.5%-32.3%), including dentists specialized (mean accuracy: 43.3% ± 20.4%; 95% CI, 12.7%-56.2%) and not specialized (mean accuracy: 16.8% ± 9.0%; 95% CI, 12.8%-20.9%) in implantology. In addition, DL tends to require lesser reading and classification time (4.5 min) than dentists who specialized (75.6 ± 31.0 min; 95% CI, 13.1-78.4) and did not specialize (91.3 ± 38.3 min; 95% CI, 74.1-108.6) in implantology. DL achieved reliable outcomes in the identification and classification of various types of DISs, and the classification accuracy performance of DL was significantly superior to that of specialized or nonspecialized dental professionals. DL as a decision support aid can be successfully used for the identification and classification of DISs encountered in clinical practice.

Long-term changes in mandibular and facial widths after mandibular setback surgery using intraoral vertical ramus osteotomy.

This study was performed to evaluate the long-term changes in mandibular width, lower facial width, and ramus angulation after intraoral vertical ramus osteotomy (IVRO) and to identify the factors influencing these changes. This retrospective study included 53 consecutive patients with mandibular prognathism who underwent IVRO with (n=33) or without (n=20) Le Fort I osteotomy. Postero-anterior cephalograms and frontal facial photographs obtained before, 1 month after, and at least 24 months after IVRO were used for measurements. A linear mixed model and paired t-tests were used to analyze temporal changes and the associated influencing factors. The mandibular width increased immediately after surgery (P<0.05), but decreased continuously thereafter. The ramus angulation showed negligible change within the first month (P>0.05) and decreased thereafter up to approximately 36 months. The amounts of mandibular setback and posterior impaction and the length of time postoperative influenced these changes. The lower facial width changed, although inconsistently, within 3mm over time (P>0.05). In conclusion, the mandibular width increased after IVRO but seemed to normalize within approximately 3 years. The lower facial width did not reflect underlying skeletal changes. Therefore, long-term transverse changes after IVRO can be considered clinically irrelevant.

A surgical strategy for severe facial asymmetry due to unilateral condylar overgrowth.

Unilateral condylar overgrowth induces severe facial asymmetry. Therefore, treatment focuses on both elimination of the condyle lesion and correction of the facial asymmetry. The aim of this report is to present three patient cases, introducing a simpler surgical method, the indications for this surgical method, and a treatment planning flow that is consistently applicable regardless of the origin of the condylar lesion. Condylectomy was performed simultaneously with orthognathic surgery, with the vertical ramus osteotomy selected as the method of ramus surgery; ipsilateral ramus surgery was not performed on the condylectomy side. This method is applicable in cases in which facial asymmetry originates solely from unilateral condylar overgrowth, and the maxilla and mandible are presumed to have been in the normal class I anteroposterior position before the onset of condylar lesion growth. After surgery, temporomandibular joint pain and/or mouth limitations were resolved, the new condyle showed satisfactory bone remodelling, and favourable facial symmetry was attained. The postoperative results were maintained long-term and there was no recurrence on the condylectomy side. This simply modified surgical strategy for facial asymmetry due to unilateral condylar overgrowth may be used in selected patients, regardless of the origin of the condylar lesion.